1. Field of the Invention
This invention relates generally to semiconductor products manufacturing, and, more particularly, to a method and apparatus for using of equipment state data and fault detection in run-to-run control of manufacturing tool operation.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today""s manufacturing processes, particularly semi-conductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
Among the important aspects in semiconductor device manufacturing are RTA control, chemical-mechanical (CMT) control , and overlay control. Overlay is one of several important steps in the photolithography area of semiconductor manufacturing. Overlay control involves measuring the misalignment between two successive patterned layers on the surface of a semiconductor device. Generally, minimization of misalignment errors is important to ensure that the multiple layers of the semiconductor devices are connected and functional. As technology facilitates smaller critical dimensions for semiconductor devices, the need for reduced of misalignment errors increases dramatically.
Generally, photolithography engineers currently analyze the overlay errors a few times a month. The results from the analysis of the overlay errors are used to make updates to exposure tool settings manually. Some of the problems associated with the current methods include the fact that the exposure tool settings are only updated a few times a month. Furthermore, currently the exposure tool updates are performed manually.
In some cases, where automatic adjustments of exposure tool settings are made on a lot-by-lot or a batch-by-batch basis, particularly adjustments that are made based upon post-process measurements, changes in the process or the manufacturing tool that result in a misalignment of the pattern on the wafer can go undetected until the post-process measurements are made. Furthermore, when some wafers, wafer lots, or wafer batches are not measured, the potential impact of misalignment problems can increase.
Generally, a set of processing steps is performed on a lot of wafers on a semiconductor manufacturing tool called an exposure tool or a stepper. The manufacturing tool communicates with a manufacturing framework or a network of processing modules. The manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface to which the stepper is connected, thereby facilitating communications between the stepper and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. Often, semiconductor devices are staged through multiple manufacturing tools for multiple processes, generating data relating to the quality of the processed semiconductor devices. Many times, inaccuracies in manufacturing processes cannot be measured because they may involve a semiconductor process characteristic that may be difficult to measure. This could cause quality problems that may otherwise be corrected if data relating to the inaccuracies had been acquired. Furthermore, delays in measurements, or reduced sampling of product wafers, can cause the quality problems to affect an increased amount of products.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In one aspect of the present invention, a method is provided for using equipment state data for controlling a manufacturing process. Initial equipment state data is acquired. At least one semiconductor device is processed using the initial equipment state data is performed. Equipment and wafer state data processing is performed using data from the processing of the semiconductor device and the initial equipment state data. A determination is made whether at least one control input parameter used for processing of the semiconductor device is to be modified in response to performing the equipment and wafer state data processing. The control input parameter is modified in response to determining that at least one the control input parameter is to be modified.
In another aspect of the present invention, an apparatus is provided for using equipment state data for controlling a manufacturing process. The apparatus of the present invention comprises: means for acquiring an initial equipment state data; means for performing a manufacturing process of at least one semiconductor device using the initial equipment state data; means for performing an equipment and wafer state data processing using data from the processing of the semiconductor device and the initial equipment state data; means for determining whether at least one control input parameter used for the process of the semiconductor device is to be modified in response to performing the equipment and wafer state data processing; and means for modifying the control input parameter in response to a determination that at least one the control input parameter is to be modified.